Qwilfish (Harysen in Japanese) are Water/Poison type Pokémon. Its origin comes from the fish, Puferfish its explosive qualites may also be insperd by deep sea mines, its name is a mix of quill and fish. Early designs of a Pokemon called Buku which is the origins of Quilfish.
In the anime Quilfish has had a few appearances, it first apperance was in the episode Snorlax Snomen were it had a very breif appearnce, it next had a maijor scene in the episode Duling Hero's were it was owned by a trainer called Harrison.It was used to fight against Misty's Corsala but is defeated, anothor main appearnce was in the episode Just add Water under the ownership of Dorian, it was used to fight Misty's Goldeen and won despite Goldeen haveing an advantage in speed. not long after a Quilfish is seen in a Pokemon Center in the episode Legend of Thunder. Many Quilfish were liveing in Lake Slowpoke in the episode Enlighten up! A Quilfish was used by a racer in the a water Chariot race in the movie Pokemon Hero's.Several Quilfish made a Apperance in Hold the Phione!